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POPULAR SCIENCE REVIEW. 
nnd guards in all trains running greater distances than twenty miles without 
stopping. "With a view of determining on the best means of complying 
with the requirements of the Board of Trade, a meeting of engineers and 
others interested in the matter has been held at York, and a series of expe- 
riments were carried out on the various systems proposed. Amongst these 
systems we may mention that of Mr. Ivamsbottom, in which a whipcord line 
is extended from the engine to the rear van, attached on the former to a 
whistle and at the latter kept in tension by a weight. If the rear guard 
pays out line, or if a passenger cuts the cord, the whistle sounds, being 
opened by a spring as soon as the tension on the cord is diminished. 
?>Ir. Harrison has a rope system in which the whistle is opened by a pull 
on the cord, the lengths of rope being permanently attached to the carriages, 
and joined between them by hooks and eyesj when the rope is pulled a 
semaphore is released and fixes itself so as to indicate the point from which 
the signal has been given. Various electrical systems were also tried. 
More recently, Mr. Latimer Clarke has produced a pneumatic system, on 
which experiments have been made at Sevenoaks. This consists of a heavy 
gong on the engine, and a smaller one in the guard’s van. Both gongs are 
struck by hammers actuated by the train itself. The gear which actuates 
tlie hammers is connected with vacuum cylinders connected with a pipe 
running the whole length of the train, from which the air is continuously 
exhausted by a pump on the tender. The pipe is in communication with 
plugs in the carriages. Any passenger pulling out one of these plugs de- 
stroys the vacuum in the pipe, the mechanism of the gongs falls into gear, 
and the gongs are sounded. This system of Mr. Clarke answered its pur- 
pose admirably in the experimental trial, and certainly appears to possess 
many merits. 
MEDICAL SCIENCE. 
Bacteria in Glanders and Farcy. — MM. Christot and Kiener have found 
bacteria in the blood of glandered horses, and very abundantly and of large 
size in the spleen and in the pus. Along with this presence of bacteria 
there was usually leucocytlia3inia. — Coinptes-Rcndus, Nov. 23. 
Re-cstahlishmcnt of tSensihility after Resection of Nerves. — A memoir by 
.MM. Arloing and Tripier was read before the French Academy, Nov. 23, 
on the efiects of resection of certain nervous trunks. Clinical facts have 
several times shown tliat after wounds which have altered or destroyed 
a portion of a nerve, sensibility returns in the integuments to which the 
nerve is distributed. MM. Arloing and Tripier made nervous resections in 
dogs, and saw sensibility reappear after a certain time in the integuments 
to whicli the branches of the nerve were distributed, and in the peripherical 
end of the nerve itself. 
The Use of Fryotin after Operations. — M. Bonjeau states that the mortality 
from amputations has in the Ilopital de St. Andr(S in Bordeaux been greatly 
reduced by administering ergotin, 30 to 50 grains per diem, for a fortnight, 
Vx'ginning its use immediately after the operation. The result lias been the 
absence, or at least the marked diminution, of suppuration. It appeared to 
